I guess I should have written a post before I found out that I actually passed my preliminary exams. But as far as I remember, this is how it went:
First test: transport. This was my weakest area, lots of math, lots of funny vector notation that I had a weak grasp on, lots of permutations of the same problems that gave me fits. I bought a copy of the seminal book in transport phenomena, and worked through a good 60% of it in the three weeks leading up to the tests. My first problem was easy - momentum balance on a plate moving up through a pool of water and causing a film to collect on the surface of the plate. Find an expression for the velocity profile of the film.
For the second problem, dbags asked me to draw a bubble at the surface of a pool of water, and then to draw it down some distance below the surface. What happens to the bubble? I fumbled for a while before realizing that the force of the column of water would cause diffusion out of the bubble until the partial pressures were equal. I think I was in denial about the surface tension contribution, because I HATE surface tension. I still don't really get it. But after being harassed about it, I added in the term, realized that the bubble would eventually disappear completely, and waited for the next pitch.
Gravie gets that look on his face that says I'm about to tell you something that will satisfy me greatly. Then he launches into a bunch of facts about a certain beetle - this beetle gathers a bubble from the surface of the water, takes it underwater with him, and uses it to breathe. Some Darwin wannabee decides to do an experiment: give the beetle pure nitrogen, pure oxygen, or a regular air bubble. To his surprise, it turns out the beetle can stay underwater longer on air than pure oxygen, why?
Then Davie whips out another beetle. THIS beetle, he tells me, has evolved a mechanism for keeping his bubble viable indefinitely - this despite the surface tension that's causing a driving force for mass transfer from the bubble into the water. How does he do it??
Then they let me out. I caught a Muller-Graves mutual head nod, which I took to mean "yup that's a pass". I was off to a good start. Thermo was next though, and I've hated thermo since the day I was born.
It started with a softball of a kinetics question about some catalyzed reaction and multiple steady states in a CSTR. The thermo question was about osmotic pressure - sophomore chemistry stuff. As soon as the words came out of the prof's mouth I knew it was going to be a train wreck - I hated osmotic pressure as a sophomore and hadn't given it a thought since. I wrote some equilibrium conditions on the board, and the prof goes, "OK, so that's what you think it is. Continue." And I was like, well that's pretty much all I got. Long awkward silence. I tried to make it into a different problem and began solving that one, but I was reeled back in. Lots of moving from one side of the board to the other, maybe I'll see the answer if I stand here... nope. I bumbled around and got nowhere for another 15 minutes, after which we were out of time (the exam had been running late so I think I only took about 35 minutes. A long 35 minutes though). Thank goodness.
Process was the next morning. I had John Prausnitz, major contributor to the concept of fugacity (still don't understand what that shit means) and elder statesman of the department. The other prof was Rachel Seagalman, admissions chair and a big question mark. I expected her to be bad cop, but she must have felt sorry for me.
I launched into a gripping schpiel about bioprocessing, in lieu of the senior design project that I can't recall a thing about. They loved it, they were intrigued, they wanted to know more. After all the process details that Steve sent me to prepare for the exam, I only got through protein A chromatography, and got cut off. OK, let's talk about some shit you don't know about now. Damn.
So Rachel wanted me to explain how to keep a fishtank clean. Obviously the first thing you do is get some of those sweet suckerfish, an activated carbon filter, and bubble some O2 through there. No problems. How do you reactivate the carbon? Whatever, eventually I got to hot water. Fish=alive!
Then Prau wanted to know about azeotropic distillation, extractive distillation, and all manner of chemE stuff upon which my grasp was quite loose. I was starting to frustrate him, aaah dammit woman why can't you just tell me the answer!! I was supposed to draw a T-x-y diagram for two components crystallizing - I pretty much completely failed to do that, until Prausnitz stomped to the board and drew it for me. This was accompanied by Rachel imploring me to "just count the phases Katie. Count the phases!! Can't you count!?!?" I could not count the phases.
Then we talked about the device that cools your microchip - a copper tube with a drop of water on it. The chip vaporizes the water, cooling the chip, and the water then condenses on the tube and rolls back to the chip to absorb more water. After that discussion, Prausnitz and Seags look at each other, and he says, "let's stop while we're ahead, shall we?" I hung my head, thanked them, and took a lap through campus to calm down before facing my classmates.
Everyone felt like shit, which seems to be the whole point of these exams, remind the smart kids how much smarter their professors are. It's an academic version of a frat hazing. But shit, I did just learn the bulk of 4 years of chemical engineering in 3 weeks. And that's something.
I'll tell you about the rest of the day later. I gotta clean my apartment.